Socioecological systems (SES) hinge on human groups and ecosystems, promoting interdependence and resilience to environmental disturbances. Climate change effects propagate from organism to biomes, likely influencing SES. In southern Brazil, Araucaria Forest is a typical SES due to the historical interaction between humans and biodiversity. We thus aimed to evaluate empirically and theoretically how climate change could disrupt this system by interviewing 97 smallholders and assessing their Traditional Ecological Knowledge (TEK). We evaluated and measured: (i) socioeconomic impact of araucaria’s nut-like seed (pinhão) trade; (ii) ethnoecological knowledge about climate change; and (iii) generated an ecosystem services network. We projected these empiric data with a projected loss of 50-70% of the Araucaria Forest due to climate change to quantify the risks of the potential disruption of this socioecological system. We found evidence that to avoid the disruption of the Araucaria Forests is paramount to value TEK holders, safeguard the historical socioecological interaction, and promote non-mutually exclusive measures in an integrative response to maintain the Araucaria Forests resilient to future disturbances.